The incidence of HIV infection among young adults continues to accelerate at alarming rates despite widespread educational efforts and dissemination of materials designed to increase awareness of risk. With young adults under the age of 25 accounting for more than half of all new HIV infections, there is an urgent need to reduce the incidence in this population. Many interventions aimed at increasing HIV knowledge have not produced substantial decreases in risky sexual behaviors, and this lack of effectiveness may be a result of differences in how young adults make decisions about abstract, prototypical situations versus specific, real-life instances. Paradoxically, young adults make safe choices when reasoning about prototypical sexual situations, yet still exhibit risky behavior in actual, real-life settings. By examining young adults' decision-making in both real and prototypical situations, we may identify differences in reasoning processes that reveal why previous interventions were ineffective and also delineate dimensions of this paradox that must be addressed in future interventions. We aim to (1) conduct qualitative research to characterize the context surrounding young adults' risky behavioral choices and apply specialized cognitive methods of discourse analysis to examine processes underlying young adults' decision-making; (2) develop and refine cognitive models of the decision-making processes used by young adults in both real-life and hypothetical situations; and (3) compare these models of decision-making to identify and separate factors or characteristics associated with healthy vs. unsafe choices in risky situations. We will recruit 30 heterosexual men and 30 heterosexual women from a local city college who will complete daily journals chronicling their sexual activity over two weeks. We will use our analyses of journal contents to guide subsequent phases of the project. These include semi-structured interviews to investigate the reasoning strategies and situational factors underlying decision-making in both (a) real-life situations as recorded in the journals and (b) a prototypical risky situation compiled from instances of unsafe sexual encounters developed from review of the journals. From the semi-structured interviews, we will implement cognitive techniques of analysis, including propositional analysis and construction of semantic networks, to model the process of decision- making in each of the two contexts. Comparison of models will reveal the factors underlying the decision-making process and how they differ in real-life and prototypical situations. We anticipate that our analysis will identify those factors that promote healthy choices and those that lead to risky behavioral choices. Our findings will provide valuable insight into the aspects of young adults' decision-making that are most critical to target in interventions.